66782913 has 16 divisors (see below), whose sum is σ = 91396800. Its totient is φ = 43352064.

The previous prime is 66782899. The next prime is 66782923. The reversal of 66782913 is 31928766.

It is a happy number.

It is not a de Polignac number, because 66782913 - 2²⁰ = 65734337 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66782923) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57345 + ... + 58497.

It is an arithmetic number, because the mean of its divisors is an integer number (5712300).

Almost surely, 2^66782913 is an apocalyptic number.

It is an amenable number.

66782913 is a deficient number, since it is larger than the sum of its proper divisors (24613887).

66782913 is a wasteful number, since it uses less digits than its factorization.

66782913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1648.

The product of its digits is 108864, while the sum is 42.

The square root of 66782913 is about 8172.0813138392. The cubic root of 66782913 is about 405.7156740808.

It can be divided in two parts, 6678 and 2913, that added together give a triangular number (9591 = T₁₃₈).

The spelling of 66782913 in words is "sixty-six million, seven hundred eighty-two thousand, nine hundred thirteen".